Correct Answer: C

Rationale: When taking isoniazid and rifampin for active tuberculosis, patients should be taught that an improvement in symptoms will likely be noticed within 2 to 3 weeks. Choice A (48 hours) is too soon to expect significant improvement in symptoms. Choice B (a week to 10 days) is also too early for noticeable improvement with this medication regimen. Choice D (4 to 6 weeks) is too far out to expect a noticeable improvement in symptoms.

Correct Answer: B

Rationale: The correct answer is to 'Avoid smoking while taking this medication' because patients taking conjugated estrogens should avoid smoking due to the increased risk of cardiovascular events. Increasing fluid intake to prevent dehydration is a good practice but not specifically related to conjugated estrogens. Increasing the intake of high-calcium foods may be beneficial for bone health but is not directly related to the medication. Taking the medication at bedtime to prevent insomnia is not a specific teaching point for conjugated estrogens.

Correct Answer: B

Rationale: Cytotoxic T cells are the key players in cell-mediated immunity as they directly attack cells displaying specific antigens. Lymphokine-producing cells (Choice A) are involved in cytokine production, while Helper T cells (Choice C) assist in activating other immune cells. Macrophages (Choice D) are phagocytic cells that engulf and digest pathogens, but they are not the primary cells responsible for directly attacking cells with specific antigens in cell-mediated immunity.

Correct Answer: B

Rationale: Swelling during acute inflammation is primarily caused by the accumulation of fluid exudate in the affected tissues. This fluid exudate contains proteins and cells that leak from blood vessels due to increased vascular permeability. Collagenase (Choice A) is an enzyme that breaks down collagen and is not directly responsible for swelling. Lymphocytic margination (Choice C) is the process where white blood cells line up along the blood vessel walls, which does not directly cause swelling. Anaerobic glycolysis (Choice D) is a metabolic process that occurs in the absence of oxygen and is not related to the mechanism of swelling in acute inflammation.

Correct Answer: C

Rationale: The correct answer is C. Oral contraceptives can be less effective when taken with certain antibiotics as they may interfere with the effectiveness of the contraceptive. It is important for patients to be aware of this interaction to consider additional contraceptive methods during antibiotic therapy. Choices A and B are incorrect as no contraceptive method is 100% effective, and oral contraceptives typically require a period of time to reach full effectiveness. Choice D is incorrect as taking oral contraceptives with food does not significantly impact their effectiveness.